Ideas on how to make a flimsy plastic sword stiffer?

I'm going to be a in a production in a few weeks and the swords for our guards just arrived yesterday. They are great, and we got them for a great price. Only problem, they are about 36 inches long and kind of flimsy. They flop a bit when swung. The plastic is solid and looks really good. Any ideas on how to stiffen them up a bit?

Did you make this instructable?

Yes, well the swords are unfortunately not hollow, and incredibly thin. Hence the flimsiness.

This puts the kibosh on any kind of internal reinforcement. So either you wrap them in something very stiff (sharpened steel keeps coming to mind....) or you bail on them and get something properly sword-like to use instead, like SCA weaponry.

You might be able to do something with fiberglass or carbon fiber, but no matter what, you'll be spending more than what you paid in the first place.

Only thing I could think of that wouldn't totally change the look or require building from scratch is getting two identical blades and laminating them together with plastic cement. Of course, then the swords wind up costing twice as much and you have all these extra hilts and pommels lying around....

Yeah, it's great stuff (see what I did there?), but I've had really bad luck with getting it to cure in enclosed spaces. I once used it to fill a severed head prop - latex skin filled with expanding foam from a can. The prop looked great when it came out of the mold, and for a week or so afterward. Then it started to get smaller and more wrinkly by the day. Last time I saw it, it was the size of a grapefruit, and looked like a giant flesh-colored raisin wearing a wig. I've used A/B ever since.

Steel. Preferably pointy and sharpened along the sides. Oh, wait, that would be a real sword, wouldn't it?

But seriously, if these are hollow, you should be able to put something like a furring strip inside to stiffen them somewhat. In fact, if they are hollow, then they will have a lenticular (football shaped) cross section. You can take advantage of that.

Carefully cut strips of wood (say 1/4" masonite or 3/8" plywood) slightly (1/16" or less) larger than the short cross-dimension. Now force-fit those strips down the center of each sword-blade. That should turn it into something more like an H-beam than a tube, and it should become much stiffer in flexion.